With increasing awareness of potential damage to the environment resulting from recyclables directed to waste landfill dumps or incineration, more industries and municipalities are implementing waste diversion and recycling programs to significantly reduce the volume of waste that must be processed in a conventional manner. However, as the rate of waste diversion and recycling has increased, processing facilities have found that certain recyclables, in particular biodegradable organic materials, have increasingly become contaminated with non-biodegradable materials due to improper separation, or materials used to package the biodegradable compost. In particular, contamination by various types of plastics is a very common problem.
Municipal and industrial compost facilities in North America and in other jurisdictions are struggling with a growing plastics contamination problem as they attempt to recycle biodegradable compost materials in an efficient and cost effective manner. A particular challenge is that there are numerous types of plastics found in compost which are diverse in shape, size and density, ranging from larger pieces of solid plastics, to thin strips of plastics torn from plastic bags and packaging. Furthermore, biodegradable organic materials often have high moisture content, making effective separation of plastics from the organic materials technically challenging. These technical challenges may result in increased wear on processing machinery, increased labour and operating costs, and a reduction in the market value of the finished compost product. At worst, the processed compost may be so contaminated by that it is unusable altogether and must ultimately be discarded as waste.
Various prior art solutions have attempted to address the problem of plastics separation with some degree of effectiveness, but existing solutions are unable to remove plastics contaminants to a sufficient level without very close monitoring of operating conditions, and possibly additional processing steps to prepare the contaminated compost material for separation.
Therefore, what is needed is an improved method and apparatus for separating plastics contaminants from compost which overcomes at least some of the limitations in the prior art.